Drought conditions pose a serious risk to the performance of integrated municipal water systems (MWS). They subject MWS to a combined effect of increased demands and decreased supplies. Both water supplies and demands are driven by variability of climate conditions such as rainfall and temperature.In this study, a conceptual model is developed to evaluate the integrated MWS reliability. In this multistage model, data are generated using Monte Carlo simulation, assuming that supply, distribution system characteristics, and demand are random variables, and preserving any existing correlation between supply and demand during drought periods.Reliability is defined as the ability of the MWS to provide an adequate amount of water for users at specific times and locations with a sufficient pressure. In this study, the performance of integrated MWS is investigated under two failure scenarios: (1) available supply is not adequate to meet the required demand; and, (2) system distribution and treatment capacity are less than the demand rate. Because the two failure modes themselves are not independent, the reliability bounds approach is used to estimate the overall reliability of integrated MWS. The use of the reliability bounds approach to estimate the integrated MWS reliability, as outlined in this research, is an innovative, powerful technique in water resources engineering.The results of this analysis provide a set of guidelines and practical strategies to help the MWS manager to detect low reliability zones in the system, and provide them with the best course of action to improve the system performance. Traditionally, MWS managers' common practices use demand reduction or pipe rehabilitation to improve the system performance during drought conditions. Unlike these common practices, this study finds that reducing the required pressure head at the demand node is the most efficient technique to improve the reliability of MWS. The significance of this finding may open a new horizon to improve the existing drought response management and practices in MWS operation.